FROM WEST PAKISTAN 73 



margin broadly rounded, posterior truncated. Dorsal margin straight, but looks 

 irregular in lateral view because of over-reaching of the dorsal ridge ; ventral margin 

 almost straight. Anterior and posterior cardinal angles well-developed particularly 

 in the left valve. Left valve slightly over-reaches the right at the anterior cardinal 

 angle and along the posterodorsal slope. Eye-tubercle distinct and rounded. Sub- 

 central-tubercle prominent. Surface reticulate with three longitudinal ridges. Dorsal 

 ridge wavy and convex upwards, it begins above the subcentral-tubercle and in the 

 posterodorsal region, curves sharply down to meet the median ridge. A strongly 

 curved ridge runs from the eye-tubercle to the subcentral-tubercle, continuing 

 posteriorly as a median ridge. Ventral ridge commences above the anteroventral 

 corner and is slightly convex downwards. There is a short, curved ridge on the 

 ventral side of the subcentral-tubercle running towards the anterior end. A marginal 

 rim runs along the anterior, ventral and posterior margins. It is high on the anterior 

 but less high along the venter and posterior. Anterior ornamented with short, 

 numerous spines. There is a large posteroventral spine. Radial pore canals simple, 

 more or less straight, some crossing one another, few seem to bifurcate, some 25 

 anteriorly. Inner margin and line of concrescence coincide ; no vestibule. Duplicature 

 of moderate width with a well-marked selvage. Hinge holamphidont with a pro- 

 jecting conical anterior tooth in the right valve. 



Dimensions (mm). 



Io. 4357 Carapace male (holotype) 

 Io. 3144 Right valve (broken) 

 Io. 3145 Carapace (juvenile) 



Comparison. This species has already been 

 obliqua sp. nov. 



Remarks. S. portentum is a very rare ostracod and has so far only been found in 

 the uppermost beds of the Lower Chocolate Clays of the Rakhi Nala section. 



Stigmatocythere calia sp. nov. 

 (Plate 36, figs. 7-9 ; Plate 37, figs. 1, 3) 



Derivation of name. Greek, kalia, bird's nest ; from a fancied appearance of 

 the ornamentation in lateral view. 



Diagnosis. A non-reticulate Stigmatocythere with straight posterior, high 

 anterior marginal rim, prominent and projecting subcentral-tubercle, dorsal and 

 ventral lines of ornamentation, posteroventral ridge, almost straight. 



Holotype. Io. 4353, a female carapace (PI. 36, figs, 8, 9 ; PI. 37, figs. 1, 3). 



Paratype. Io. 4304. 



Material. 15 specimens from the locality below from five horizons (sample 

 nos. 24148, 24150 to 24153). GSP. BM. 2589. 



Type locality. Zao River section. 



Type horizon. Upper Chocolate Clays, sample no. 24151. 



L 



H 



W 



0-71 



o-37 



0-32 



— 



o-37 



— 



o-59 



o-35 



0-29 



compared 



with 



Stigmatocythere 



